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MaskedStretch and Stars Cores

by Alejandro Tombolini

Processing

When applying MaskedStretch tool, cores of saturated stars will be protected and will remain as they are, independently of the increasing bright in the periphery. A possible alternative to solve this is repair the stars cores before stretching. The following image of Antares will be useful to show the reparation.

MaskedStretch

First I have applied MaskedStretch tool to a crop of the image with Antares using the default values. As expected the center of the star does not look fine.

MaskedStretch

Over a clone of the linear image apply the Repaired HSV Separation script. Set the desired levels to Clip Shadows and Repair level and check V- no repairs for the scrip to generate also the Unrepaired V.

MaskedStretch

You will get four new images:

  • Unrepaired V
  • V
  • Sv
  • H

MaskedStretch

I have seen in some cases that is better to generate the new image using the Unrepaired V instead of V. Using ChannelCombination tool generate the new image.

MaskedStretch

The center of the stars look better now in the linear image:

MaskedStretch

Finally apply the same Masked stretch process to the repaired image.

MaskedStretch

See Bob Andersson post about Repaired HSV Separation Script.

Last Update: 18/12/2014 00:59 UT

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